#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vll vector<ll>
#define len(x) (ll)x.size()
const ll inf = 1e9, infl = 1e18;
const ll MOD = 1e9 + 7;
const ll maxn = 2e5 + 5;
ll n, m, k = 0;
ll tree[maxn * 4];
void upd(ll x, ll y, ll l = 1, ll r = n, ll v = 1){
if(l == r) return tree[v] = y, void();
ll md = (l + r) >> 1;
if(x <= md) upd(x, y, l, md, v << 1);
else upd(x, y, md + 1, r, v << 1 | 1);
tree[v] = min(tree[v << 1], tree[v << 1 | 1]);
}
ll get(ll x, ll y, ll l = 1, ll r = n, ll v = 1){
if(r < x or tree[v] > y) return - 1;
if(l == r) return l;
ll md = (l + r) >> 1, e = get(x, y, l, md, v << 1);
if(e != - 1) return e;
return get(x, y, md + 1, r, v << 1 | 1);
}
void _() {
cin >> n >> m;
for(ll i = 1; i <= n * 4; i ++) tree[i] = inf;
while(m --){
char c;
ll x, y, e;
cin >> c >> x >> y;
if(c == 'M'){
upd(y, x);
} else{
e = get(y, x);
cout << e << '\n';
}
}
}
signed main() {
cin.tie(0)->sync_with_stdio(0);
ll t = 1;
// cin >> t;
while(t --) _();
}
