#include <cstdio> #include <cstring> #include <algorithm> #define n 50 #define INF 1000000000 using namespace std; int l_paper[51][51][51][51],rec[51][51]; int h1,w1,h2,w2; int main(){ int i,j,k,l,p; scanf("%d %d %d %d",&h1,&w1,&h2,&w2); for(i=1;i<=n;i++){ for(j=1;j<=n;j++){ rec[i][j]=INF; if(i==1 || j==1){ rec[i][j]=max(i,j); continue; } if(i==j){ rec[i][j]=1; continue; } for(k=1;k<i;k++) rec[i][j]=min(rec[i][j],rec[k][j]+rec[i-k][j]); for(k=1;k<j;k++) rec[i][j]=min(rec[i][j],rec[i][k]+rec[i][j-k]); } } for(i=1;i<=h1;i++){ for(j=1;j<=w1;j++){ for(k=1;k<i;k++){ for(l=1;l<j;l++){ l_paper[i][j][k][l]=INF; l_paper[i][j][k][l]=min(l_paper[i][j][k][l],rec[k][j-l]+rec[i-k][j]); l_paper[i][j][k][l]=min(l_paper[i][j][k][l],rec[i-k][l]+rec[i][j-l]); for(p=1;p<j-l;p++) l_paper[i][j][k][l]=min(l_paper[i][j][k][l],rec[p][i]+l_paper[i][j-p][k][l]); for(p=1;p<l;p++) l_paper[i][j][k][l]=min(l_paper[i][j][k][l],rec[p][i-k]+l_paper[i][j-p][k][l-p]); for(p=1;p<k;p++) l_paper[i][j][k][l]=min(l_paper[i][j][k][l],rec[p][j-l]+l_paper[i-p][j][k-p][l]); for(p=1;p<i-k;p++) l_paper[i][j][k][l]=min(l_paper[i][j][k][l],rec[p][j]+l_paper[i-p][j][k][l]); } } } }printf("%d",l_paper[h1][w1][h2][w2]); return 0; }