n, X = map(int, input().split())
A = list(map(int, input().split()))
sum_total = sum(A)

if sum_total < X:
    print("No")
else:
    # Precompute suffix sums for pruning
    suffix_sum = [0] * (n + 1)
    for i in range(n-1, -1, -1):
        suffix_sum[i] = A[i] + suffix_sum[i+1]
    
    result = None
    path = ['x'] * n  # Initialize all as not selected
    
    def dfs(i, current_sum):
        global result
        if current_sum == X:
            result = path.copy()
            return True
        if i >= n:
            return False
        if current_sum > X:
            return False
        if current_sum + suffix_sum[i] < X:
            return False
        
        # Try not selecting A[i]
        if dfs(i + 1, current_sum):
            return True
        
        # Try selecting A[i]
        path[i] = 'o'
        if dfs(i + 1, current_sum + A[i]):
            return True
        path[i] = 'x'  # Backtrack
        
        return False
    
    if dfs(0, 0):
        print(''.join(result))
    else:
        print("No")