#include <bits/stdc++.h>
#define ll long long
#define MOD 1000000007
#define EPS 1e-10
#define rep(i,n) for(int i=0;i<(int)(n);++i)
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;--i)
#define srep(i,s,t) for(int i=(int)(s);i<(int)(t);++i)
#define each(a,b) for(auto (a): (b))
#define all(v) (v).begin(),(v).end()
#define len(v) (int)(v).size()
#define zip(v) sort(all(v)),v.erase(unique(all(v)),v.end())
#define cmx(x,y) x=max(x,y)
#define cmn(x,y) x=min(x,y)
#define fi first
#define se second
#define pb push_back
#define show(x) cout<<#x<<" = "<<(x)<<endl
#define spair(p) cout<<#p<<": "<<p.fi<<" "<<p.se<<endl
#define svec(v) cout<<#v<<":";rep(kbrni,v.size())cout<<" "<<v[kbrni];cout<<endl
#define sset(s) cout<<#s<<":";each(kbrni,s)cout<<" "<<kbrni;cout<<endl
#define smap(m) cout<<#m<<":";each(kbrni,m)cout<<" {"<<kbrni.first<<":"<<kbrni.second<<"}";cout<<endl

using namespace std;

typedef pair<int,int> P;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<double> vd;
typedef vector<P> vp;
typedef vector<string> vs;

template<typename T> class min_cost_flow{
public:
    struct edge {
        int to,cap;
        T cost;
        int rev;
    };
	using pti = pair<T,int>;
    vector<vector<edge> > G;
	vector<T> h,dist;
	vector<int> prevv,preve;
	T inf;
    int V;
    min_cost_flow(int node_size){
        V = node_size;
		inf = numeric_limits<T>::max() / 100;
        G.resize(V), h.resize(V), dist.resize(V), prevv.resize(V), preve.resize(V);
	}
    void add_edge(int from, int to, int cap, T cost){
        G[from].push_back((edge){to, cap, cost, (int)G[to].size()});
        G[to].push_back((edge){from, 0, -cost, (int)G[from].size() - 1});
    }
    T solve(int s,int t,int f){
        T res = 0;
		fill(h.begin(),h.end(),0);
        while(f > 0){
            priority_queue<pti,vector<pti>,greater<pti> > que;
            fill(dist.begin(),dist.end(),inf);
            dist[s] = 0;
            que.push(pti(0,s));
            while(!que.empty()){
                pti p = que.top();
                que.pop();
                int v = p.second;
                if(dist[v] < p.first){
                    continue;
                }
                rep(i,G[v].size()){
                    edge& e = G[v][i];
                    if(e.cap > 0 && dist[e.to] > dist[v] + e.cost + h[v] - h[e.to]){
                        dist[e.to] = dist[v] + e.cost + h[v] - h[e.to];
                        prevv[e.to] = v, preve[e.to] = i;
                        que.push(pti(dist[e.to], e.to));
                    }
                }
            }
            if(dist[t] == inf){
                return -1;
            }
            rep(i,V){
                h[i] += dist[i];
            }
            int d = f;
            for(int v = t; v != s; v = prevv[v]){
                d = min(d, G[prevv[v]][preve[v]].cap);
            }
            f -= d;
            res += d * h[t];
            for(int v = t; v != s;v = prevv[v]){
                edge& e = G[prevv[v]][preve[v]];
                e.cap -= d;
                G[v][e.rev].cap += d;
            }
        }
        return res;
    }
};

int main()
{
	int n,e,f;
	cin >> n >> e >> f;
	min_cost_flow<int> mc(n);
	rep(i,e){
		int u,v,c,d;
		cin >> u >> v >> c >> d;
		mc.add_edge(u,v,c,d);
	}
	cout << mc.solve(0,n-1,f) << "\n";
    return 0;
}

Measured memory_bytes: 3176