#include <stdio.h>
#include <string.h>
/*int ispalindrome(int x){
    char str[20];
    sprintf(str,"%d",x);
    int i = 0, j = strlen(str)- 1;
    while(i < j){
        if(str[i] != str[j]){
            return 0;
        }
        i++;
        j--;
    }
    return 1;
}
int main(){
    int n;
    if(scanf("%d", &n) != 1){
        printf("Invalid input");
        return 0;
    }
    int num = n + 1;
    while(1){
        if(ispalindrome(num)){
            printf("%d", num);
            break;
        }
        num++;
    }
    return 0;
}*/
#include <ctype.h>
int ispalindrome(int n) {
    int reversed = 0, original = n,digits;
    while(n > 0) {
        reversed = reversed * 10 + digits;
        n /= 10;
    }
    return (reversed==original);
}
/*int isvalidnumber(char str[]) {
    int i = 0;
    if(str[0] == '-') return 0;
    while(str[i]) {
        if(!isdigit(str[i])){
            return 0;
            i+;
        }
    }
    return 1;
}*/
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(!ispalindrome(next)){
        next++;
    }
    printf("%d", next);
}