#include<stdio.h>
#include<string.h>

int main() {
    char str[105];
    scanf("%s",str);
    
    int len=strlen(str);
    
    //Lenght is guaranteed even in problem,but safe-check
    if(len%2!=0) {
        printf("Invalid input");
        return 0;
    }
    for (int i=0;i<len;i+=2) {
        int d1=str[i] -'0';
        int d2=str[i+1] -'0';
    }