public static int minNum(int samDaily, int kellyDaily, int difference) {
    // Write your code here
    
    int samsolved = difference + samDaily;
    int kellysolved = kellyDaily;
    int count=1;
    
    if(kellyDaily==samDaily) return -1;
      
    while(samsolved-kellysolved>=0){
        samsolved=samsolved+samDaily;
        kellysolved=kellysolved+kellyDaily;
        count++;
    }
    return count;
    }