#include <cstdio>
#include <cctype>
#include <algorithm>
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4.1,sse4.2,avx,avx2,popcnt,tune=native")
#pragma GCC optimize(2)
#include <immintrin.h>
#include <emmintrin.h>
using namespace std;
template<class code>inline code read(const code &a){
    code x=0;short w=0;char ch=0;
    while(!isdigit(ch)){w|=ch=='-';ch=getchar();}
    while(isdigit(ch)){x=(x<<3)+(x<<1)+(ch^48);ch=getchar();}
    return w?-x:x;
}
int main(){
	int a,b,c,d;
	a=read(a),b=read(b),c=read(c),d=read(d);
	if(a==0&b==0){printf("0");return 0;} 
	if(a==0){printf("%d",d);return 0;}
	if(a==b&c==1){printf("1");return 0;}
	if(a==b&d==1){printf("%d",min(c+d,d*2));return 0;}
	if(a==0||b==0){printf("%d",min(c+d,d));return 0;}
	printf("%d",min(c+d,d*2)); 
    return 0;
}