from collections import deque


def main():
    from sys import stdin, setrecursionlimit
    # setrecursionlimit(1000000)
    input = stdin.readline
    def iinput(): return int(input())
    def sinput(): return input().rstrip()
    def i0input(): return int(input()) - 1
    def linput(): return list(input().split())
    def liinput(): return list(map(int, input().split()))
    def miinput(): return map(int, input().split())
    def li0input(): return list(map(lambda x: int(x) - 1, input().split()))
    def mi0input(): return map(lambda x: int(x) - 1, input().split())
    INF = 1000000000000000000
    MOD = 1000000007

    N, M = miinput()
    H = liinput()

    G = [[] for _ in [0] * N]
    RG = [[] for _ in [0] * N]
    DEG = [0] * N
    RDEG = [0] * N

    for _ in [0] * M:
        x, y = mi0input()
        G[x].append(y)
        DEG[y] += 1
        RG[y].append(x)
        RDEG[x] += 1
    
    def solve(g, s, deg):
        dp = [[-INF, -INF] for _ in [0] * N]
        dp[s][0] = 0
        dp[s][1] = 0
        que = deque()

        for i in range(N):
            if deg[i] == 0:
                que.append(i)
        
        while que:
            u = que.popleft()
            for v in g[u]:
                if H[v] > H[u]:
                    dp[v][1] = max(dp[v][1], dp[u][0] + H[v] - H[u])
                else:
                    dp[v][0] = max(dp[v][0], dp[u][0], dp[u][1])
                deg[v] -= 1
                if deg[v] == 0:
                    que.append(v)
        
        return dp
    
    ans = max(solve(G, 0, DEG)[-1])
    if ans >= 0:
        print(ans)
    else:
        print(-1)

    ans = max(solve(RG, N-1, RDEG)[0])
    if ans >= 0:
        print(ans)
    else:
        print(-1)

main()