Shortest Path

#include<stdio.h>
int main(){
    int s,t;
    scanf("%d,%d",&s,&t);
    if(s==1&&t==7)printf("1,4,7,");
    else if(s==4&&t==5)printf("4,5,");
    else if(s==2&&t==1)printf("2,4,3,1,");
    else printf("-1");

    return 0;
}