#include <bits/stdc++.h>
using namespace std;
#define MAXN 200100
int vet[MAXN], tree[4*MAXN];
void update(int node, int l, int r, int idx, int val){
if(idx<l or idx>r){
return;
}
if(l==idx and r==idx){
tree[node]=val;
return;
}
int mid = (l+r)>>1;
update(2*node, l, mid, idx, val);
update(2*node+1, mid+1, r, idx, val);
tree[node] = min(tree[2*node], tree[2*node+1]);
}
int query(int node, int tl, int tr, int l, int val){
if(l > tr){
return 0x3f3f3f3f;
}
if(tree[node]>val){
return 0x3f3f3f3f;
}
if(tl==tr){
return tl;
}
int mid = (tl+tr) >> 1;
int p1 = query(2*node, tl, mid, l, val);
if(p1 == 0x3f3f3f3f){
return query(2*node+1, mid+1, tr, l, val);
}
return p1;
}
int n, q;
int main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);
cin >> n >> q;
// build
memset(vet, 0x3f3f3f3f, sizeof vet);
memset(tree, 0x3f3f3f3f, sizeof tree);
for(int i=1; i<=q; i++){
char o;
cin >> o;
if(o=='M'){
int x, a;
cin >> x >> a;
update(1, 1, n, a, x);
}
if(o=='D'){
int y, b;
cin >> y >> b;
int ans = query(1, 1, n, b, y);
if(ans==0x3f3f3f3f){
cout << -1 << endl;
}
else{
cout << query(1, 1, n, b, y) << endl;
}
}
}
return 0;
}
