#include <bits/stdc++.h>

using namespace std;

typedef long long LL;
int f[301000];
char ch[3];

int n;

int main(){
	scanf("%d",&n);
	
	f[1]=1;
	for (int i=2;i<=300000;i++){
		if (f[i]) continue;
		for (int j=i+i;j<=300000;j+=i) f[j]=1;
	}

	long long p=0;
	int bo=0;
	
	int x0=41,x1;
	int pp=73;
	for (int i=1;i<=40;i++){
		printf("2\n");
		fflush(stdout);
		/*
		x1=x0*2%pp;
		printf("!!%d %d\n",x1,x0);
		x0=x1;
		*/
		scanf("%s",ch);
		if (ch[0]=='=') bo=1;
		
		p*=2;
		if (ch[0]=='<') p++;
		if (ch[0]=='O') return 0;
	}
	//cout << p<<endl;
	if (bo){
		printf("2\n");
		fflush(stdout);
		scanf("%s",ch);
		return 0;
	}
	
	//    X0/P > (p/2^40)

	long long q=1LL<<40;
	int ans=0;
	for (int i=3;i<=n;i++)
		if (f[i]==0){
			LL x=ceil(p*i*1.0/q);
			//cout << i<<" "<<x<<endl;
			if (x*q<(p+1)*i) ans=i;
		}
	printf("%d\n",ans);
	fflush(stdout);
	scanf("%s",ch);


	return 0;
}