/*       无汇源有上下界的网络流*/#include <iostream>#include <cstring>#define ms(a,b) memset(a,b,sizeof a)using namespace std;const int MAXN = 209;struct node {    int u, v, c, ne;} edge[MAXN * MAXN << 2];int pHead[MAXN*MAXN], SS, ST, T, ncnt, ans;int Gup[MAXN][MAXN], Glow[MAXN][MAXN], st[MAXN], ed[MAXN], cap[MAXN][MAXN], tflow;void addEdge (int u, int v, int c) {    edge[++ncnt].v = v, edge[ncnt].c = c, edge[ncnt].u = u;    edge[ncnt].ne = pHead[u], pHead[u] = ncnt;    edge[++ncnt].v = u, edge[ncnt].c = 0, edge[ncnt].u = v;    edge[ncnt].ne = pHead[v], pHead[v] = ncnt;}int SAP (int pStart, int pEnd, int N) {    int numh[MAXN], h[MAXN], curEdge[MAXN], pre[MAXN];    int cur_flow, flow_ans = 0, u, neck, i, tmp;    ms (h, 0); ms (numh, 0); ms (pre, -1);    for (i = 0; i <= N; i++) curEdge[i] = pHead[i];    numh[0] = N;    u = pStart;    while (h[pStart] <= N) {        if (u == pEnd) {            cur_flow = 1e9;            for (i = pStart; i != pEnd; i = edge[curEdge[i]].v)                if (cur_flow > edge[curEdge[i]].c) neck = i, cur_flow = edge[curEdge[i]].c;            for (i = pStart; i != pEnd; i = edge[curEdge[i]].v) {                tmp = curEdge[i];                edge[tmp].c -= cur_flow, edge[tmp ^ 1].c += cur_flow;            }            flow_ans += cur_flow;            u = neck;        }        for ( i = curEdge[u]; i != 0; i = edge[i].ne) {            if (edge[i].v > N) continue; //重要!!!            if (edge[i].c && h[u] == h[edge[i].v] + 1)     break;        }        if (i != 0) {            curEdge[u] = i, pre[edge[i].v] = u;            u = edge[i].v;        }        else {            if (0 == --numh[h[u]]) continue;            curEdge[u] = pHead[u];            for (tmp = N, i = pHead[u]; i != 0; i = edge[i].ne) {                if (edge[i].v > N) continue; //重要!!!                if (edge[i].c)  tmp = min (tmp, h[edge[i].v]);            }            h[u] = tmp + 1;            ++numh[h[u]];            if (u != pStart) u = pre[u];        }    }    return flow_ans;}int solve (int n) {    SS = n + 1, ST = n + 2;    for (int i = 1; i <= n; i++) {        if (ed[i]) addEdge (SS, i, ed[i]);        if (st[i]) addEdge (i, ST, st[i]);    }    int tem = SAP (SS, ST, ST);    if (tem != tflow) return 0;    else              return 1;}int n, m;int main() {    ios::sync_with_stdio (0);    ncnt = 1;    cin >> n >> m;    for (int i = 1, u, v, x, y; i <= m; i++) {        cin >> u >> v >> x >> y;        Gup[u][v] = y, Glow[u][v] = x;        st[u] += x, ed[v] += x;        tflow += x;        addEdge (u, v, y - x);    }    if (solve (n) ) {        cout << "YES\n";        for (int i = 2, x, y; i <= m * 2; i += 2) {            x = edge[i].u, y = edge[i].v;            cout << Gup[x][y]-edge[i].c << ‘\n‘;        }    }    else        cout << "NO\n";    return 0;}