#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
namespace fastio
{
static constexpr size_t buf_size = 1 << 18;
static constexpr size_t integer_size = 20;
static constexpr size_t block_size = 10000;
static char inbuf[buf_size + 1] = {};
static char outbuf[buf_size + 1] = {};
static char block_str[block_size * 4 + 1] = {};
static constexpr uint64_t power10[] = {1,
10,
100,
1000,
10000,
100000,
1000000,
10000000,
100000000,
1000000000,
10000000000,
100000000000,
1000000000000,
10000000000000,
100000000000000,
1000000000000000,
10000000000000000,
100000000000000000,
1000000000000000000,
10000000000000000000u};
struct Scanner
{
private:
size_t pos, end;
void load()
{
end = fread(inbuf, 1, buf_size, stdin);
inbuf[end] = '\0';
}
void reload()
{
size_t len = end - pos;
memmove(inbuf, inbuf + pos, len);
end = len + fread(inbuf + len, 1, buf_size - len, stdin);
inbuf[end] = '\0';
pos = 0;
}
void skip_space()
{
while (inbuf[pos] <= ' ')
{
if (__builtin_expect(++pos == end, 0))
reload();
}
}
char get_next()
{
return inbuf[pos++];
}
char get_next_nonspace()
{
skip_space();
return inbuf[pos++];
}
public:
Scanner()
{
load();
}
void scan(char &c)
{
c = get_next_nonspace();
}
void scan(std::string &s)
{
skip_space();
s = "";
do
{
size_t start = pos;
while (inbuf[pos] > ' ')
pos++;
s += std::string(inbuf + start, inbuf + pos);
if (inbuf[pos] != '\0')
break;
reload();
} while (true);
}
template <class T> typename std::enable_if<std::is_integral<T>::value, void>::type scan(T &x)
{
char c = get_next_nonspace();
if (__builtin_expect(pos + integer_size >= end, 0))
reload();
bool neg = false;
if (c == '-')
neg = true, x = 0;
else
x = c & 15;
while ((c = get_next()) >= '0')
x = x * 10 + (c & 15);
if (neg)
x = -x;
}
template <class Head, class... Others> void scan(Head &head, Others &...others)
{
scan(head);
scan(others...);
}
template <class T> Scanner &operator>>(T &x)
{
scan(x);
return *this;
}
};
struct Printer
{
private:
size_t pos = 0;
void flush()
{
fwrite(outbuf, 1, pos, stdout);
pos = 0;
}
void pre_calc()
{
for (size_t i = 0; i < block_size; i++)
{
size_t j = 4, k = i;
while (j--)
{
block_str[i * 4 + j] = k % 10 + '0';
k /= 10;
}
}
}
static constexpr size_t get_integer_size(uint64_t n)
{
if (n >= power10[10])
{
if (n >= power10[19])
return 20;
if (n >= power10[18])
return 19;
if (n >= power10[17])
return 18;
if (n >= power10[16])
return 17;
if (n >= power10[15])
return 16;
if (n >= power10[14])
return 15;
if (n >= power10[13])
return 14;
if (n >= power10[12])
return 13;
if (n >= power10[11])
return 12;
return 11;
}
else
{
if (n >= power10[9])
return 10;
if (n >= power10[8])
return 9;
if (n >= power10[7])
return 8;
if (n >= power10[6])
return 7;
if (n >= power10[5])
return 6;
if (n >= power10[4])
return 5;
if (n >= power10[3])
return 4;
if (n >= power10[2])
return 3;
if (n >= power10[1])
return 2;
return 1;
}
}
public:
Printer()
{
pre_calc();
}
~Printer()
{
flush();
}
void print(char c)
{
outbuf[pos++] = c;
if (__builtin_expect(pos == buf_size, 0))
flush();
}
void print(const char *s)
{
while (*s != 0)
{
outbuf[pos++] = *s++;
// if (pos == buf_size) flush();
if (__builtin_expect(pos == buf_size, 0))
flush();
}
}
void print(const std::string &s)
{
for (auto c : s)
{
outbuf[pos++] = c;
// if (pos == buf_size) flush();
if (__builtin_expect(pos == buf_size, 0))
flush();
}
}
template <class T> typename std::enable_if<std::is_integral<T>::value, void>::type print(T x)
{
if (__builtin_expect(pos + integer_size >= buf_size, 0))
flush();
if (x < 0)
print('-'), x = -x;
size_t digit = get_integer_size(x);
size_t len = digit;
while (len >= 4)
{
len -= 4;
memcpy(outbuf + pos + len, block_str + (x % block_size) * 4, 4);
x /= block_size;
}
memcpy(outbuf + pos, block_str + x * 4 + (4 - len), len);
pos += digit;
}
template <class Head, class... Others> void print(const Head &head, const Others &...others)
{
print(head);
print(' ');
print(others...);
}
template <class... Args> void println(const Args &...args)
{
print(args...);
print('\n');
}
template <class T> Printer &operator<<(const T &x)
{
print(x);
return *this;
}
};
}; // namespace fastio
fastio::Scanner fin;
fastio::Printer fout;
using namespace std;
#ifndef yoshi_likes_e4
#define endl '\n'
#endif
#define problem ""
#define multitest 0
#define debug(x) cerr << #x << " = " << x << endl;
template <typename T, typename Op> struct StaticRangeProduct
{
static const size_t B = 10;
std::vector<T> pref, suf, cur;
std::vector<std::vector<T>> spt;
Op op;
StaticRangeProduct(std::vector<T> p, Op opr) : op(opr)
{
cur = p;
const size_t SZ = (cur.size() + B - 1) / B * B;
cur.resize(SZ);
pref.resize(SZ);
suf.resize(SZ);
for (size_t i = 0; i < SZ; i++)
{
if (i % B == 0)
pref[i] = cur[i];
else
pref[i] = op(pref[i - 1], cur[i]);
}
for (size_t i = SZ - 1;; i--)
{
if (i % B == B - 1)
suf[i] = cur[i];
else
suf[i] = op(cur[i], suf[i + 1]);
if (i == 0)
break;
}
spt.assign(1, std::vector<T>(SZ / B));
for (size_t i = 0; i < SZ; i += B)
spt[0][i / B] = pref[i + B - 1];
for (size_t shift = 2; shift * B < SZ; shift *= 2)
{
spt.push_back(std::vector<T>(SZ / B));
bool flag = 0;
for (size_t k = 0; k * B < SZ; k += shift, flag ^= 1)
{
if (flag)
{
spt.back()[k] = spt[0][k];
for (size_t x = k + 1; x < std::min(SZ / B, k + shift); x++)
spt.back()[x] = op(spt.back()[x - 1], spt[0][x]);
}
else if (k + shift <= SZ / B)
{
spt.back()[k + shift - 1] = spt[0][k + shift - 1];
for (size_t x = k + shift - 2;; x--)
{
spt.back()[x] = op(spt[0][x], spt.back()[x + 1]);
if (x == k)
break;
}
}
}
}
}
T query(size_t l, size_t r)
{
T res;
if (l / B == r / B)
{
res = cur[l];
for (size_t i = l + 1; i <= r; i++)
res = op(res, cur[i]);
}
else
{
res = suf[l];
if (l / B + 1 <= r / B - 1)
{
if (l / B + 1 == r / B - 1)
res = op(res, spt[0][l / B + 1]);
else
{
size_t lg = __lg((r / B - 1) ^ (l / B + 1));
res = op(res, spt[lg][l / B + 1]);
res = op(res, spt[lg][r / B - 1]);
}
}
res = op(res, pref[r]);
}
return res;
}
};
struct Mat
{
int A[5][5];
Mat()
{
for (int i = 0; i < 5; i++)
for (int j = 0; j < 5; j++)
A[i][j] = 1e9;
}
};
auto weirdMatMul = [](Mat a, Mat b) {
Mat c;
for (int i = 0; i < 5; i++)
for (int j = 0; j < 5; j++)
for (int k = 0; k < 5; k++)
c.A[i][k] = min(c.A[i][k], a.A[i][j] + b.A[j][k]);
return c;
};
void init()
{
}
void Yoshi()
{
int K, N, M, O;
fin >> K >> N >> M >> O;
vector<Mat> mats(N / K + 1);
while (M--)
{
int u, v, t;
fin >> u >> v >> t;
mats[u / K].A[u % K][v % K] = t;
}
StaticRangeProduct<Mat, decltype(weirdMatMul)> matq(mats, weirdMatMul);
while (O--)
{
int a, b;
fin >> a >> b;
if (a / K >= b / K)
fout << -1 << endl;
else
{
int d = matq.query(a / K, b / K - 1).A[a % K][b % K];
if (d > 5e8)
fout << -1 << endl;
else
fout << d << endl;
}
}
}
signed main()
{
#ifndef yoshi_likes_e4
if (fopen(problem ".inp", "r"))
{
freopen(problem ".inp", "r", stdin);
freopen(problem ".out", "w", stdout);
}
#endif
init();
int t = 1;
#if multitest
cin >> t;
#endif
while (t--)
Yoshi();
}
