C :

#include<stdio.h>
 
 
int main() {
    // 把三个数读进来，并拆开
    int a, b, c, i;
    int n;
    scanf("%d", &n);
    for (i = 100; i < 1000; i++) {
        int k = i;
        c = k % 10;
        k = k / 10;
        b = k % 10;
        a = k / 10;
        int acb = a * 100 + c * 10 + b;
        int bac = b * 100 + a * 10 + c;
        int bca = b * 100 + c * 10 + a;
        int cab = c * 100 + a * 10 + b;
        int cba = c * 100 + b * 10 + a;
        if (acb + bac + bca + cab + cba == n) {printf("The number is %d\n", i);
            break;
        }
    }
    if (i == 1000) {
        printf("The sum you calculated is wrong!\n");
    }
 
 
 
}