#include<stdio.h>
int main()
{
	int min, mid, max;
	min = 0;
	max = 1003;
	char res1[8], res2[8];
	while (max - min > 1)
	{
		mid = (max + min) / 2;
		printf("? %d\n", mid);
		fflush(stdout);
		scanf("%s", res1);
		if (res1[0] == 's')
		{
			min = mid;
			continue;
		}
		printf("? %d\n", mid + 1);
		fflush(stdout);
		scanf("%s", res2);
		if (res2[0] == 's')
			min = mid + 1;
		else
			max = mid;
	}
	printf("! %d\n", min);
	return 0;
}