// LUOGU_RID: 98493765
#include<bits/stdc++.h>
using namespace std;
inline int read(int x) {
	cout<<"+ "<<x<<endl;
	int ret; cin>>ret; return ret;
}
int n,sum=0,lst=0;
inline bool check(int k) {
	int q=(k+n-sum%n)%n,p=read(q);
	sum=(sum+q);
	if(p>lst) {
		lst=p;
		return true;
	}
	return false;
}
signed main() {
	cin>>n;
	int l=1,r=n-1,res=0;
	while(l<=r) {
		int mid=(l+r)>>1;
		if(check(mid)) res=mid,r=mid-1;
		else l=mid+1;
	}
	cout<<"! "<<n-res+sum<<endl;
	return 0;
}