#include <iostream>
#include <string>
#include <cassert>
using namespace std;
const int MAX = 5;
struct Matrix
{
int a[MAX][MAX];
Matrix()
{
for (int i=0;i<MAX;i++)
for (int j=0;j<MAX;j++)
a[i][j] = 0;
}
void add(const Matrix &o)
{
for (int i=0;i<MAX;i++)
for (int j=0;j<MAX;j++)
a[i][j] += o.a[i][j];
}
void sub(const Matrix &o)
{
for (int i=0;i<MAX;i++)
for (int j=0;j<MAX;j++)
a[i][j] -= o.a[i][j];
}
void show() const
{
for (int i=0;i<MAX;i++) {
for (int j=0;j<MAX;j++) {
cout << a[i][j] << " ";
}
cout << "\n";
}
}
int swapdistance() const
{
int mtot = 0;
int si[MAX], sj[MAX];
for (int i=0;i<MAX;i++)
si[i] = 0;
for (int j=0;j<MAX;j++)
sj[j] = 0;
for (int i=0;i<MAX;i++)
for (int j=0;j<MAX;j++)
{
mtot += a[i][j];
si[i] += a[i][j];
sj[j] += a[i][j];
}
for (int node=0;node<MAX;node++)
if (si[node] != sj[node])
return -1;
Matrix aux = *this;
int cycles = 0;
// 1-cycles
for (int i=0;i<MAX;i++)
{
cycles += aux.a[i][i];
aux.a[i][i] = 0;
}
// 2-cycles
for (int i=0;i<MAX;i++)
for (int j=0;j<i;j++)
{
int c = min(aux.a[i][j], aux.a[j][i]);
cycles += c;
aux.a[i][j] -= c;
aux.a[j][i] -= c;
}
// 3-cycles
for (int i=0;i<MAX;i++)
for (int j=0;j<i;j++)
for (int k=0;k<j;k++)
{
int c;
#define do3(i,j,k) c = min(aux.a[i][j], min(aux.a[j][k], aux.a[k][i])); cycles += c; aux.a[i][j] -= c; aux.a[j][k] -= c; aux.a[k][i] -= c;
do3(i,j,k);
do3(i,k,j);
}
// 4-cycles
for (int i=0;i<MAX;i++)
for (int j=0;j<i;j++)
for (int k=0;k<j;k++)
for (int l=0;l<k;l++)
{
int c;
#define do4(i,j,k,l) c = min(min(aux.a[i][j], aux.a[j][k]), min(aux.a[k][l], aux.a[l][i])); cycles += c; aux.a[i][j] -= c; aux.a[j][k] -= c; aux.a[k][l] -= c; aux.a[l][i] -= c;
do4(i,j,k,l);
do4(i,j,l,k);
do4(i,k,j,l);
do4(i,k,l,j);
do4(i,l,j,k);
do4(i,l,k,j);
}
// 5-cycles
int remainingEdges = 0;
for (int i=0;i<MAX;i++)
for (int j=0;j<MAX;j++)
remainingEdges += aux.a[i][j];
assert(remainingEdges % 5 == 0);
cycles += remainingEdges / 5;
return mtot - cycles;
}
};
const int MAXN = 250000;
Matrix fenwick[MAXN+1];
// logical fenwick array has indexes from 0 to MAXN-1, inclusive
// fenwickAdd(pos) adds the given value to index pos
// fenwickQuery(pos) returns the sum of range [0, pos)
void fenwickAdd(int pos, const Matrix &value)
{
assert(0 <= pos);
assert(pos < MAXN);
for (pos++; pos <= MAXN ; pos += pos&(-pos))
fenwick[pos].add(value);
}
Matrix fenwickQuery(int pos)
{
assert(0 <= pos);
assert(pos <= MAXN);
Matrix ret;
for (; pos > 0 ; pos -= pos&(-pos))
ret.add(fenwick[pos]);
return ret;
}
int charValues[256];
string globalA, globalB;
void init(string a, string b)
{
globalA = a;
globalB = b;
charValues['A'] = 0;
charValues['C'] = 1;
charValues['G'] = 2;
charValues['T'] = 3;
charValues['U'] = 4;
Matrix mat;
for (int i=0;i<int(a.size());i++)
{
int x = charValues[int(a[i])];
int y = charValues[int(b[i])];
mat.a[x][y] = 1;
fenwickAdd(i, mat);
mat.a[x][y] = 0;
}
}
void modify(int k, int i, char xChar)
{
Matrix mat;
int x = charValues[int(globalA[i])];
int y = charValues[int(globalB[i])];
mat.a[x][y] -= 1;
if (k == 0)
globalA[i] = xChar;
else
globalB[i] = xChar;
x = charValues[int(globalA[i])];
y = charValues[int(globalB[i])];
mat.a[x][y] += 1;
fenwickAdd(i, mat);
}
int get_distance(int i,int j)
{
Matrix mat = fenwickQuery(j+1);
mat.sub(fenwickQuery(i));
return mat.swapdistance();
}
