from collections import deque
from heapq import heapify,heappop,heappush,heappushpop
from copy import copy,deepcopy
from itertools import permutations,combinations
from collections import defaultdict,Counter
from bisect import bisect_left
# from math import gcd,ceil,floor,factorial
# from fractions import gcd
from functools import reduce
from pprint import pprint

def myinput():
    return map(int,input().split())

def mylistinput(n):
    return [ list(myinput()) for _ in range(n) ]

def mycol(data,col):
    return [ row[col] for row in data ]

def mysort(data,col,reverse_flag):
    data.sort(key=lambda x:x[col],reverse=reverse_flag)
    return data

def mymax(data):
    M = -1*float("inf")
    for i in range(len(data)):
        m = max(data[i])
        M = max(M,m)
    return M

def mymin(data):
    m = float("inf")
    for i in range(len(data)):
        M = min(data[i])
        m = min(m,M)
    return m

def myoutput(ls,space=True):
    if space:
        if len(ls)==0:
            print(" ")
        elif type(ls[0])==str:
            print(" ".join(ls))
        elif type(ls[0])==int:
            print(" ".join(map(str,ls)))
        else:
            print("Output Error")
    else:
        if len(ls)==0:
            print("")
        elif type(ls[0])==str:
            print("".join(ls))
        elif type(ls[0])==int:
            print("".join(map(str,ls)))
        else:
            print("Output Error")

n,m = myinput()
a = list(myinput())
bc = mylistinput(m)

a.sort()
bc = mysort(bc,1,True)

d = []
for i in range(m):
    b = bc[i][0]
    c = bc[i][1]
    d_add = [c]*b
    d.extend(d_add)
    if len(d)>=n:
        d = d[:n]
        break
d.sort()
# print(d)

for i in range(n):
    e = d.pop()
    if a[i]<e:
        a[i]= e
    else:
        break
# print(a)
ans = sum(a)
print(ans)

### FIXED CODE ###

from collections import deque
from heapq import heapify,heappop,heappush,heappushpop
from copy import copy,deepcopy
from itertools import permutations,combinations
from collections import defaultdict,Counter
from bisect import bisect_left
# from math import gcd,ceil,floor,factorial
# from fractions import gcd
from functools import reduce
from pprint import pprint

def myinput():
    return map(int,input().split())

def mylistinput(n):
    return [ list(myinput()) for _ in range(n) ]

def mycol(data,col):
    return [ row[col] for row in data ]

def mysort(data,col,reverse_flag):
    data.sort(key=lambda x:x[col],reverse=reverse_flag)
    return data

def mymax(data):
    M = -1*float("inf")
    for i in range(len(data)):
        m = max(data[i])
        M = max(M,m)
    return M

def mymin(data):
    m = float("inf")
    for i in range(len(data)):
        M = min(data[i])
        m = min(m,M)
    return m

def myoutput(ls,space=True):
    if space:
        if len(ls)==0:
            print(" ")
        elif type(ls[0])==str:
            print(" ".join(ls))
        elif type(ls[0])==int:
            print(" ".join(map(str,ls)))
        else:
            print("Output Error")
    else:
        if len(ls)==0:
            print("")
        elif type(ls[0])==str:
            print("".join(ls))
        elif type(ls[0])==int:
            print("".join(map(str,ls)))
        else:
            print("Output Error")

n,m = myinput()
a = list(myinput())
bc = mylistinput(m)

a.sort()
bc = mysort(bc,1,True)

d = []
for i in range(m):
    b = bc[i][0]
    c = bc[i][1]
    d_add = [c]*b
    d.extend(d_add)
    if len(d)>=n:
        d = d[:n]
        break
d.sort()
# print(d)

for i in range(n):
    if len(d)==0:
        break
    e = d.pop()
    if a[i]<e:
        a[i]= e
    else:
        break
# print(a)
ans = sum(a)
print(ans)