#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef long long ll;
typedef pair<int,int> PII;
const ll mod=1000000007;
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

const int N=1010;
char g[N][N];
int n,m,a,b,r,c;
void nosol() {
	puts("NO");
	exit(0);
}
void sol() {
	rep(i,0,n) rep(j,0,m) if (g[i][j]=='<') {
		if (a==0) g[i][j]=g[i][j+1]='.'; else --a;
	}

	rep(i,0,n) rep(j,0,m) if (g[i][j]=='^') {
		if (b==0) g[i][j]=g[i+1][j]='.'; else --b;
	}
	puts("YES");
	rep(i,0,n) puts(g[i]);
	exit(0);
}
int main() {
	scanf("%d%d%d%d",&n,&m,&a,&b);
	rep(i,0,n) rep(j,0,m) g[i][j]='.';
	r=0; c=0;
	rep(i,0,n) rep(j,0,m-1) if (g[i][j]=='.') {
		g[i][j]='<'; g[i][j+1]='>'; r++;
	}
	rep(i,0,n-1) rep(j,0,m) if (g[i][j]=='.') {
		g[i][j]='^'; g[i+1][j]='v'; c++;
	}
	if (a>r) nosol();
	if (r>=a&&c>=b) sol();
	rep(i,0,n-1) rep(j,0,m-1) if (g[i][j]=='<'&&g[i][j+1]=='>'&&g[i+1][j]=='<'&&g[i+1][j+1]=='>') {
		if (r-2>=a) {
			g[i][j]=g[i][j+1]='^';
			g[i+1][j]=g[i+1][j+1]='v';
			r-=2; c+=2;
			if (r>=a&&c>=b) sol();
		} else if (r-1>=a&&g[i+2][j+2]=='.') {
			g[i+1][j]='^';
			g[i+2][j]='v';
			g[i+1][j+1]='.';
			g[i+2][j+1]='<';
			g[i+2][j+2]='>';
			--r; ++c;
			if (r>=a&&c>=b) sol();
		}
	}
	nosol();
}