// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution4 {
public static void main(String[] args){
int X=10;
int Y=85;
int D=30;
int M=Y-X;
int reti=0;
if (X==Y){
reti=0;
}else{
if (M<=D){
reti=1;
}else{
if(M % D==0){
reti=(M / D);
}else{
if((M / D) * D>M){
reti=(M / D)-1;
}
if((M / D) * D<M){
reti=(M / D)+1;
}
}
}
}
System.out.println(reti);
}
}