#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <queue>
#include <vector>
#include <stack>
#include <set>
#include <cmath>
#include <bitset>
#define lson node << 1
#define rson node << 1 | 1
using namespace std;
#define ll long long
const ll maxn = 5e5 + 10;
ll read() {
    char c = getchar();
    ll x = 0;
    ll flag = 1;
    while (c < '0' || c > '9') {
        if (c == '-')
            flag = -1;
        c = getchar();
    }
    while (c >= '0' && c <= '9') {
        x = x * 10 + c - 48;
        c = getchar();
    }
    x *= flag;
    return x;
}
int l = 1, r = 1e9;
int x;
int main() {
    while (1) {
        int mid = (l + r) >> 1;
        printf("%d\n", mid);
        fflush(stdout);
        scanf("%d", &x);
        if (x == 1) {
            r = mid - 1;
        } else if (x == -1) {
            l = mid + 1;
        } else
            break;
    }
    // printf("%d",l);
    return 0;
}