#include<stdio.h>
int ispalidrome(int n)
{
    int reversed= 0,orginal=n, digits;
    while(n>0){
        digits= n%10;
        reversed = reversed*10+digits;
        n/=10;
    }
    return(reversed == orginal);
}
int main(){
    float tempInput;
    int input;
    if(scanf("%f",&tempInput)!=1){
        printf("Invalid input");
        return 0;
    }
    input=(int)tempInput;
    if(tempInput !=input || input<0){
        printf("Invalid input");
        return 0;
    }
    int next=input+1;
    while(!spalindrome(next))
    {
        next++;
        
    }
    printf("%d",next);
    return 0;
}