import sys
input = sys.stdin.readline
import heapq

N,M=map(int,input().split())

EDGE=[dict() for i in range(2*N+1)]

for i in range(M):
    u,v,c,d=map(int,input().split())
    EDGE[u][v]=[c,1]
    EDGE[u][N+v]=[d,1]
    EDGE[u][N+u]=[0,float("inf")]
    EDGE[N+u][u]=[0,float("inf")]
    EDGE[N+v][u]=[d,0]

    EDGE[v][u]=[c,1]
    EDGE[v][N+u]=[d,1]
    EDGE[v][N+v]=[0,float("inf")]
    EDGE[N+v][v]=[0,float("inf")]
    EDGE[N+u][v]=[d,0]


start=1
goal=N

BACK=[-1]*(2*N+1)
LA=0

for flow in range(2):
    ANS=[float("inf")]*(2*N+1)
    Q=[(0,start)]
    ANS[start]=0
 
    while Q:
        time,fr = heapq.heappop(Q)
        if time > ANS[fr]:
            continue

        for to in EDGE[fr]:
            cost,flow=EDGE[fr][to]
            
            if flow>0 and ANS[to]>ANS[fr]+cost:
                
                ANS[to]=ANS[fr]+cost
                BACK[to]=fr
                heapq.heappush(Q,(ANS[to],to))

    LA+=ANS[goal]
 
    NOW=goal
    while NOW!=start:
        fr=BACK[NOW]
        EDGE[fr][NOW][1]-=1
        EDGE[NOW][fr][1]+=1

        NOW=fr

print(LA)