//El Parsieto
#include<bits/stdc++.h>
#define Fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define rep(i, l, r) for(ii i = l; i < r; i++)
#define per(i, l, r) for(ii i = r - 1; i >= l; i--)
#define min(x, y) (x < 1 ? y : y < 1 ? x : x < y ? x : y)
#define pb push_back
#define X first
#define Y second
typedef long long ll;
typedef int ii;
constexpr ii xn = 4e5 + 5;
using namespace std;
ii s[xn], e;
void upd(ii v, ii l, ii r, ii x, ii y) {
if(x < l || r <= x) return;
if(r - l < 2) { s[v] = y; return; }
ii m = l + r >> 1; ii rc = v + (m - l) * 2;
upd(v + 1, l, m, x, y), upd(rc, m, r, x, y);
s[v] = min(s[v + 1], s[rc]);
}
void get(ii v, ii l, ii r, ii x, ii y) {
if(r <= x || !s[v] || s[v] > y) return;
if(r - l < 2) { e = l + 1; return; }
ii m = l + r >> 1; ii rc = v + (m - l) * 2;
get(v + 1, l, m, x, y);
if(e > 0) return;
get(rc, m, r, x, y);
}
int main() {
Fast; ii n, q, x, y; cin >> n >> q;
while(q--) {
char o; cin >> o >> y >> x; x--;
if(o == 'M') upd(0, 0, n, x, y);
else {
e = -1, get(0, 0, n, x, y);
cout << e << '\n';
}
}
}
