#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC push_options
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#include<bits/stdc++.h>
#include <xmmintrin.h>
#include <immintrin.h>
using namespace::std;
__attribute__((constructor))void init(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(15);}
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/priority_queue.hpp>
#include<ext/pb_ds/tag_and_trait.hpp>
// #include <boost/multiprecision/cpp_dec_float.hpp>
// #include <boost/multiprecision/cpp_int.hpp>
// namespace mp = boost::multiprecision;
// typedef mp::number<mp::cpp_dec_float<0>> cdouble;
// typedef mp::cpp_int cint;
template<typename T>using pbds=__gnu_pbds::tree<T,__gnu_pbds::null_type,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T>using pbds_map=__gnu_pbds::tree<T,T,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T,typename E>using hash_map=__gnu_pbds::gp_hash_table<T,E>;
template<typename T>using pqueue =__gnu_pbds::priority_queue<T, greater<T>,__gnu_pbds::rc_binomial_heap_tag>;
typedef long long lint;
#define INF (1LL<<60)
#define IINF (1<<30)
#define LINF (9223372036854775807LL)
#define EPS (1e-10)
#define endl ('\n')
#define MOD 1000000007LL
//#define MOD 998244353LL
typedef vector<lint> vec;
typedef vector<vector<lint>> mat;
typedef vector<vector<vector<lint>>> mat3;
typedef vector<string> svec;
typedef vector<vector<string>> smat;
template<typename T>inline void numout(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i<INF/2?i:"INF";f=1;}cout<<endl;}
template<typename T>inline void numout2(T t){for(auto i:t)numout(i);}
template<typename T>inline void output(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i;f=1;}cout<<endl;}
template<typename T>inline void output2(T t){for(auto i:t)output(i);}
template<typename T>inline void _output(T t){bool f=0;for(lint i=0;i<t.size();i++){cout<<f?"":" "<<t[i];f=1;}cout<<endl;}
template<typename T>inline void _output2(T t){for(lint i=0;i<t.size();i++)output(t[i]);}
#define rep(i,n) for(lint i=0;i<lint(n);++i)
#define repi(i,a,b) for(lint i=lint(a);i<(lint)(b);++i)
#define rrep(i,n) for(lint i=lint(n)-1;i>=0;--i)
#define rrepi(i,a,b) for(lint i=lint(b)-1;i>=lint(a);--i)
#define irep(i) for(lint i=0;;++i)
#define all(n) begin(n),end(n)
#define dist(a,b,c,d) sqrt(pow(a-c,2)+pow(b-d,2))
inline lint gcd(lint A,lint B){return B?gcd(B,A%B):A;}
inline lint lcm(lint A,lint B){return A/gcd(A,B)*B;}
// inline cint cgcd(cint A,cint B){return B?cgcd(B,A%B):A;}
// inline cint clcm(cint A,cint B){return A/cgcd(A,B)*B;}
bool chmin(auto& s,const auto& t){bool res=s>t;s=min(s,t);return res;}
bool chmax(auto& s,const auto& t){bool res=s<t;s=max(s,t);return res;}
const vector<lint> dx={1,0,-1,0,1,1,-1,-1};
const vector<lint> dy={0,1,0,-1,1,-1,1,-1};
#define SUM(v) accumulate(all(v),0LL)
auto call=[](auto f,auto... args){return f(f,args...);};

template<typename T>
struct min_cost_flow{
    int v;
    constexpr static T inf=1LL<<60;
    T ans=0;
    struct edge{
        int to;
        T cap,cost;
        int rev;
    };
    vector<T>p;
    vector<vector<edge*>>e;//辺のキャパシティ
    vector<T>d;
    min_cost_flow(int v):v(v){
        p.resize(v+2);
        e.resize(v+2);
        d.resize(v,0);
    }
    void add_edge(int from,int to,T cap,T cost){
        if(cost>=0){
            e[from].push_back(new edge{to,cap,cost,(int)e[to].size()});
            e[to].push_back(new edge{from,0,-cost,(int)e[from].size()-1});
        }
        else{
            e[to].push_back(new edge{from,cap,-cost,(int)e[from].size()});
            e[from].push_back(new edge{to,0,cost,(int)e[to].size()-1});
            ans+=cap*cost;
            d[from]-=cap;d[to]+=cap;
        }
    }
    T flow(){
        int s=v,t=v+1;
        vector<int>prev(v+2),pree(v+2);
        T f=T();
        for(int i=0;i<v;i++){
            if(d[i]>0)add_edge(s,i,d[i],0),f+=d[i];
            if(d[i]<0)add_edge(i,t,-d[i],0);
        }
        d.resize(v,0);
        while(f){
            priority_queue<pair<T,int>,vector<pair<T,int>>,greater<pair<T,int>>>que;
            que.emplace(0,s);
            vector<T>di(v+2,inf);
            vector<T>prev(v+2),pree(v+2);
            di[s]=0;
            while(!que.empty()){
                T c;int now;
                tie(c,now)=que.top();
                que.pop();
                int idx=0;
                for(auto d:e[now]){
                    if(d->cap&&di[d->to]>c+d->cost+p[now]-p[d->to]){
                        di[d->to]=c+d->cost+p[now]-p[d->to];
                        prev[d->to]=now;
                        pree[d->to]=idx;
                        que.emplace(di[d->to],d->to);
                    }
                    ++idx;
                }
            }
            if(di[t]==inf)return -1;
            for(int i=0;i<v+2;i++)p[i]+=di[i];
            T k=f;
            for(int i=t;i!=s;i=prev[i]){
                k=min(k,e[prev[i]][pree[i]]->cap);
            }
            f-=k;
            ans+=k*p[t];
            for(int i=t;i!=s;i=prev[i]){
                auto pre=e[prev[i]][pree[i]];
                pre->cap-=k;
                e[i][pre->rev]->cap+=k;
            }
        }
        return ans;
    }
    T run(int s,int t,T f){
        d[s]+=f;
        d[t]-=f;
        return flow();
    }
};

int main(){
    lint n,m,f;
    cin>>n>>m>>f;
    min_cost_flow<lint> mf(n);
    rep(i,m){
        lint a,b,c,d;
        cin>>a>>b>>c>>d;
        mf.add_edge(a,b,c,d);
    }
    cout<<mf.run(0,n-1,f)<<endl;
}


Measured memory_bytes: 3376