#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 2e5 + 3, inf = 1e9 + 9;
struct ST {
#define lc (n << 1)
#define rc ((n << 1) + 1)
int t[4 * N];
ST() {
memset(t, 0, sizeof t);
}
inline void pull(int n) {
t[n] = min(t[lc], t[rc]);
}
void build(int n, int b, int e) {
if (b == e) {
t[n] = inf;
return;
}
int mid = (b + e) >> 1;
build(lc, b, mid);
build(rc, mid + 1, e);
pull(n);
}
void upd(int n, int b, int e, int i, int val) {
if (i < b || e < i) return;
if (b == e) {
t[n] = val;
return;
}
int mid = (b + e) >> 1;
upd(lc, b, mid, i, val);
upd(rc, mid + 1, e, i, val);
pull(n);
}
int query(int n, int b, int e, int i, int val) {
if (t[n] > val || e < i) return inf;
if (b == e) {
return b;
}
int mid = (b + e) >> 1;
return min(query(lc, b, mid, i, val), query(rc, mid + 1, e, i, val));
}
}t;
void solve() {
int n, m;
cin >> n >> m;
t.build(1, 1, n);
while (m--) {
char c;
int x, y;
cin >> c >> x >> y;
if (c == 'M') {
t.upd(1, 1, n, y, x);
} else {
int ans = t.query(1, 1, n, y, x);
if (ans == inf) ans = -1;
cout << ans << '\n';
}
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int t = 1;
// cin >> t;
while (t--) {
solve();
}
return 0;
}
