#define _USE_MATH_DEFINES
 
#include <iostream>
#include <iomanip>
#include <sstream>
 
#include <algorithm>
#include <cmath>
 
#include <string>
//#include <array>
#include <list>
#include <queue>
#include <vector>
#include <complex>
#include <set>
#include <map>
 
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
 
#define PII pair<int,int>
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////
const int LenMax = 1001;
int dp[LenMax][LenMax];
int LCS(string A,string B){
	int aLen = A.size();
	int bLen = B.size();
	for(int i = 0; i < aLen; ++i){
		dp[i][0] = 0;
	}
	for(int j = 0; j < bLen; ++j){
		dp[0][j] = 0;
	}
	for(int i = 1; i <= aLen; ++i){
		for(int j = 1; j <= bLen; ++j){
			if( A[i-1] == B[j-1] ){
				dp[i][j] = dp[i-1][j-1] + 1;
			}else{
				dp[i][j] = max( dp[i][j-1],dp[i-1][j-1] );
			}
		}
	}

	return dp[aLen][bLen];
}

int main(void){
    std::cin.tie(0); 
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    //cout << setprecision(16);//
	
	int n,m;
	string S,T;
	cin>>n>>m>>S>>T;
	int Len;
	Len = LCS(S,T);

	int ans;
	if( S.size() > T.size() ){
		ans = S.size() - Len;
	}else{
		ans = T.size() - Len;
	}
	P(ans);
	return 0;
}