N,M=map(int,input().split())
A=list(map(int,input().split()))
edges=[]
for i in range(N):
    edges.append([i,N+i,-A[i]])
for _ in range(M):
    a,b,c=map(int,input().split())
    edges.append([N+a-1,b-1,c])
ans=[10**40 for _ in range(2*N)]
ans[0]=0
for i in range(2*N+2):
    update=False
    for a,b,c in edges:
        if ans[b]>ans[a]+c:
            ans[b]=ans[a]+c
            update=True
    #print(ans)
    if not update:
        break

    if i==2*N+1:
        print('inf')
        exit(0)
print(-ans[-1])