#include<stdio.h>
#include<string.h>
int main(){
    char msg[1005];
    int start,L;
    if(fgets(msg,sizeof(msg),stdin)==NULL)return 0;
    if(n > 0 && msg[n-1] == '\n'){
        msg[n-1] = '\0';
        n--;
    }
    if(scanf("%d",&start) != 1) return 0;
    if(scanf("%d",&L) != 1) return 0;
    if(L < 1 || start < 0 || start >=(int)n || start + L > (int)n){
        printf("Invalid input\n");
    }
        for(int i = 0; i < L; ++i){
            putchar(msg[start + i]);
        }
        putchar('\n');
    }
    return 0;
 }