#include <algorithm>#include <iostream>#include <cstdio>#include <cctype>using namespace std;int read(){ int x=0,f=1; char ch=getchar(); while (!isdigit(ch)) f=ch=='-'?-1:f,ch=getchar(); while (isdigit(ch)) x=x*10+ch-'0',ch=getchar(); return x*f;}const int N=200005;const int M=200005;const int E=M<<1;const int LGN=18;int DFN[N],low[N],last[N],high[N],bel[N],fa[N],conid[N],stack[N],LOG[N],size[N],sum[N][2];int tov[E],nxt[E],rev[E];int anc[N][LGN];int n,m,q,tot,idx,cnt,btot,top;bool res;void insert(int x,int y,int r=0){tov[++tot]=y,rev[tot]=tot+r,nxt[tot]=last[x],last[x]=tot;}void tarjan(int x,int e){ DFN[x]=low[x]=++idx,conid[x]=btot,stack[++top]=x; for (int i=last[x],y;i;i=nxt[i]) if (i!=e) if (!DFN[y=tov[i]]) tarjan(y,rev[i]),low[x]=min(low[x],low[y]); else low[x]=min(low[x],DFN[y]); if (DFN[x]==low[x]) { int y; fa[++cnt]=tov[e]; do { y=stack[top--],bel[y]=cnt; }while (x!=y); }}void dfs(int x){ DFN[x]=++idx,size[x]=1; for (int i=last[x],y;i;i=nxt[i]) high[y=tov[i]]=high[x]+1,dfs(y),size[x]+=size[y];}void PRe(){ for (int i=1;i<=cnt;++i) if (fa[i]) fa[i]=bel[fa[i]]; for (;tot;nxt[tot]=rev[tot]=tov[tot]=0,--tot); for (int i=1;i<=cnt;++i) last[i]=DFN[i]=0; idx=0; for (int i=1;i<=cnt;++i) if (fa[i]) insert(fa[i],i),anc[i][0]=fa[i]; LOG[1]=0; for (int i=2;i<=cnt;++i) LOG[i]=LOG[i-1]+(1<<LOG[i-1]+1==i); for (int j=1;j<=LOG[cnt];++j) for (int i=1;i<=cnt;++i) anc[i][j]=anc[anc[i][j-1]][j-1]; for (int i=1;i<=cnt;++i) if (!fa[i]) high[i]=1,dfs(i);}int adjust(int x,int h){ for (int i=LOG[high[x]];i>=0;--i) if (high[anc[x][i]]>=h) x=anc[x][i]; return x;}int lca(int x,int y){ if (high[x]>high[y]) swap(x,y); y=adjust(y,high[x]); if (x==y) return x; for (int i=LOG[high[x]];i>=0;--i) if (anc[x][i]!=anc[y][i]) x=anc[x][i],y=anc[y][i]; return fa[x];}bool judge(int x){return sum[DFN[x]+size[x]-1][0]-sum[DFN[x]-1][0]&&sum[DFN[x]+size[x]-1][1]-sum[DFN[x]-1][1];}int main(){ freopen("network.in","r",stdin),freopen("network.out","w",stdout); n=read(),m=read(),q=read(); for (int i=1,x,y;i<=m;++i) x=read(),y=read(),insert(x,y,1),insert(y,x,-1); for (int i=1;i<=n;++i) if (!DFN[i]) ++btot,tarjan(i,0); pre(); res=1; for (int i=1,x,y,z;i<=q;++i) { x=read(),y=read(); if (conid[x]!=conid[y]) { res=0; break; } x=bel[x],y=bel[y],z=lca(x,y); ++sum[DFN[x]][0],--sum[DFN[z]][0],++sum[DFN[y]][1],--sum[DFN[z]][1]; } for (int i=1;i<=cnt;++i) sum[i][0]+=sum[i-1][0],sum[i][1]+=sum[i-1][1]; for (int i=1;i<=cnt&&res;++i) if (judge(i)) res=0; printf(res?"Yes/n":"No/n"); fclose(stdin),fclose(stdout); return 0;}
