171205_2902_KMP는 왜 KMP일까?

//https://www.acmicpc.net/problem/2902 #include <iostream>

#include <string>

using namespace std;

int main()

{

string s;

cin >> s;

int l=s.size();

cout << s[0];

for(int i=0; i<l; i++)

{

if(s[i]=='-') cout << s[i+1];

}

}