#include <stdio.h>

int main(){
    long N;
    scanf("%ld",&N);

    int n = 1;
    int count = 0;
    while (1){
        if (2*n <= N){
            n *= 2;
            count++;
        }else{
            break;
        }
    }

    if (N-n == 0){
        printf("%d\n",count);
    }else{
        printf("%d\n",count+1);
    }

}