/**************************************************************Problem: 1061User: BLADEVILLanguage: PascalResult: AcceptedTime:1496 msMemory:1028 kb
****************************************************************///By BLADEVIL
varn, m                        :longint;pre, other, len, cost       :array[0..50010] of longint;last                        :array[0..2010] of longint;l                           :longint;source, sink                :longint;ans                         :longint;flag                        :array[0..1020] of boolean;dis, que, father            :array[0..1020] of longint; function min(a,b:longint):longint;
beginif a>b then min:=b else min:=a;
end;procedure connect(a,b,c,d:longint);
begin  inc(l);pre[l]:=last[a];last[a]:=l;other[l]:=b;len[l]:=c;cost[l]:=d;
end;procedure init;
vari                           :longint;x, y, z                     :longint;beginread(n,m);source:=n+2; sink:=source+1;x:=0;l:=1;for i:=1 to n dobeginread(y);if y-x>0 thenbeginconnect(source,i,y-x,0);connect(i,source,0,0);end elsebeginconnect(i,sink,x-y,0);connect(sink,i,0,0);end;x:=y;end;connect(n+1,sink,x,0);connect(sink,n+1,0,0);for i:=1 to m dobeginread(x,y,z);connect(x,y+1,maxlongint div 10,z);connect(y+1,x,0,-z);end;for i:=2 to n+1 dobeginconnect(i,i-1,maxlongint div 10,0);connect(i-1,i,0,0);end;
end;function spfa:boolean;
varh, t, cur                   :longint;q, p                        :longint;
beginfilldword(dis,sizeof(dis) div 4,maxlongint div 10);que[1]:=source;dis[source]:=0;h:=0; t:=1;while t<>h dobeginh:=h mod 1010+1;cur:=que[h];flag[cur]:=false;q:=last[cur];while q<>0 dobeginp:=other[q];if len[q]>0 thenif dis[p]>dis[cur]+cost[q] thenbeginfather[p]:=q;dis[p]:=dis[cur]+cost[q];if not flag[p] thenbegint:=t mod 1010+1;que[t]:=p;flag[p]:=true;end;end;q:=pre[q];end;end;if dis[sink]=maxlongint div 10 then exit(false) else exit(true);
end;procedure update;
varlow, cur                    :longint;
begincur:=sink;low:=maxlongint;while cur<>source dobeginlow:=min(low,len[father[cur]]);cur:=other[father[cur] xor 1];end;cur:=sink;while cur<>source dobegindec(len[father[cur]],low);inc(len[father[cur] xor 1],low);ans:=ans+low*cost[father[cur]];cur:=other[father[cur] xor 1];end;
end;procedure main;
beginwhile spfa doupdate;writeln(ans);
end;begininit;main;
end.