#include <iostream>
using namespace std;
int mod = 1e9+7;
const int N = 1e5+10;
int dp[N][2];

int main() {
	int n; cin>>n;
	for(int i=0;i<n;i++) {
		int a; cin>>a;
		if(a > 50) {
			dp[i+1][1] = (dp[i][1] + dp[i][0] + 1)%mod;
			dp[i+1][0] = (dp[i][1] + dp[i][0])%mod;
		}
		if(a < 50) {
			dp[i+1][1] = (2*dp[i][1])%mod;
			dp[i+1][0] = (2*dp[i][0] + 1)%mod;
		}
		if(a == 50) {
			dp[i+1][1] = dp[i][1];
			dp[i+1][0] = dp[i][0];
		}
	}
	cout<<dp[n][1];
	return 0;
}