#include<stdio.h>

const unsigned long long mod=1000000007;
long long p[1000000];
long c;
typedef struct {
	long time;
	unsigned long long h;
} first;
first f[100000];

long search(){
	
}

int main(){
	long n,m,i,l,r,k;
	unsigned long long now=0;
	char query;
	scanf("%ld %ld",&n,&m);
	p[0]=1;
	for(i=0;i<n;i++){
		p[i+1]=p[i]*mod;
	}
	f[0].time=0;
	f[0].h=0;
	c=1;
	l=0;
	for(i=0;i<m;i++){
		getchar();
		scanf("%c",&query);
		if(query=='!'){ //add
			scanf("%ld %ld %ld",&l,&r,&k);
			now+=(unsigned long long)(p[r]-p[l])*k;
			for(l=0;l<c;l++){
				if(f[l].h==now) break;
			}
			if(c==l){
				f[c].time=i+1;
				f[c].h=now;
				c++;
			}
		}else{ // query=='?' question
			printf("%ld\n",f[l].time);
		}
	}
	return 0;
}