#include <stdio.h>
#include <stdlib.h>

int main()
{   int a,r,l,m,c2;

    char s = '0';
    printf("Enter maximum number = \n");
    scanf("%d",&a);
    c2 = log2(a);
    ++c2;
    printf("I guess for +- %d attempts\n",c2);
    m = a/2;
    r = a;
    l = 0;
    printf("If your number more enter + if your number less enter - in other cases enter =\n");
    printf("%d\n",m);
    while (s != '=')
    {

        scanf("%s",&s);

        if ( s == '+')
        {
            l = m;
            m = ceil(m+r)/2;

            printf("Mid = %d\n",m);

        }

        else if (s == '-')
        {   r = m;
            m = ceil(m+l)/2;
            printf("Mid = %d\n",m);
        }
    }

    return 0;
}