import sys

def main():
    try:
        input_data = sys.stdin.read().split()
        N = int(input_data[0])
        A = input_data[1]
        if len(A) != N:
            raise ValueError
        elif N < 1 or N > 5e5:
            raise ValueError
    except:
        print("Invalid input")
        exit(1)
        
    if A[0] == '0':
        dp0 = 1
    else:
        dp0 = 0
    dp1 = 1

    for prev_char, curr_char in zip(A, A[1:]):
        new_dp0 = dp0
        if prev_char == '1' and curr_char == '0':
            new_dp0 = (new_dp0 + dp1)
            
        new_dp1 = (dp1 + dp0)
        
        dp0 = new_dp0
        dp1 = new_dp1
        
    ans = dp0
    if A[-1] == '1':
        ans = (ans + dp1) % 998244353
        
    print(ans)
    
if __name__ == "__main__":
    main()