Problem:
Score : 100 points

Problem Statement

Snuke has a grid consisting of three squares numbered 1, 2 and 3.
In each square, either 0 or 1 is written. The number written in Square i is s_i.

Snuke will place a marble on each square that says 1.
Find the number of squares on which Snuke will place a marble.

Constraints

Each of s_1, s_2 and s_3 is either 1 or 0.

Input

Input is given from Standard Input in the following format:

s_{1}s_{2}s_{3}

Output

Print the answer.

Sample Input 1

101

Sample Output 1

2

A marble will be placed on Square 1 and 3.

Sample Input 2

000

Sample Output 2

0

No marble will be placed on any square.

Solution in C (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
 
 
int main()
{
 
    char  s[4];
    int cnt=0;
  int i;
 // 整数の入力
    scanf("%s", s);
//    printf("%s\n",s);

  for(i=0;i < 3 ;i++ ){
//    printf("%c\n",s[i]);
    if(49 == s[i]){ 
     cnt = cnt + 1;
//     printf("%d\n",cnt);
              }
  }
     printf("%d\n", cnt);
 
    return 0;
}