Rockethon 2014 problem A - Genetic Engineering solution

Rockethon 2014 problem A - Genetic Engineering :  http://codeforces.com/contest/391/problem/A

Rockethon 2014 problem A - Genetic Engineering solution :

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;

int main() {
    int cnt, r;
    char s[105], c;
    scanf("%s\n", s);
    c=s[0];
    cnt=1;
    r=0;
    for(int i=1; i<strlen(s); i++) {
        if(s[i]!=c) {
             if(cnt%2==0) r++;
             cnt=1;
             c=s[i];
        }
        else cnt++;
    }
    if(cnt%2==0) r++;
    printf("%d\n", r);
    return 0;
}