#include <bits/stdc++.h>
using namespace std;
#define loop(i,b,e) for(int i=b;i<=e;i++)
#define loop2(i,e,b) for(int i=e;i>=b;i--)
typedef long long ll;
typedef unsigned long long ull;

int n;
int ans = 1e6;
int m[5][5];

void solve(int x,int y,int curr) {
    if (ans == n)
        return;
    if (abs(curr - n) < abs(ans - n) || curr==n)
        ans = curr;
    if (x>=4 || y>=3 || (x==3 && y==0) || (x == 3 && y == 2))
        return;
    solve(x + 1, y, curr);
    solve(x, y + 1, curr);
    int prev = 1e9;
    int prev2 = abs(curr - n);
    while(curr<n && prev!=prev2){
        prev = prev2;
        curr = (curr * 10) + m[x][y];
        solve(x + 1, y, curr);
        solve(x, y + 1, curr);
        prev2 = abs(curr - n);
    }
}

int main() {
    scanf("%d",&n);
    int c = 1;
    loop(i, 0, 3)
        loop(j, 0, 2) {
        m[i][j] = c;
        c++;
    }
    m[3][0] = 1e6;
    m[3][1] = 0;
    m[3][2] = 1e6;
    solve(0,0,0);
    printf("%d",ans);
}