I,T,F,r=int,True,False,range
t=input().split()
H,W,K,A,a=I(t[0]),I(t[1]),I(t[2]),[],[]
s=[[I(i) for i in input()]for i in r(H)]
e=[[T if s[i][j]>4 else F for j in r(W)] for i in r(H)]
for i1 in r(H):
for j1 in r(W):
if e[i1][j1]==T:
l,p,u=[[i1,j1]],s[i1][j1],[[F for i in r(W)] for j in r(H)]
u[i1][j1]=T
for m in r(K-1):
M,P=-1,[-1,-1]
for L in l:
if 0<L[0]:
if s[L[0]-1][L[1]]>M and u[L[0]-1][L[1]]==F:M,P=s[L[0]-1][L[1]],[L[0]-1,L[1]]
if L[0]<H-1:
if s[L[0]+1][L[1]]>M and u[L[0]+1][L[1]]==F:M,P=s[L[0]+1][L[1]],[L[0]+1,L[1]]
if 0<L[1]:
if s[L[0]][L[1]-1]>M and u[L[0]][L[1]-1]==F:M,P=s[L[0]][L[1]-1],[L[0],L[1]-1]
if L[1]<W-1:
if s[L[0]][L[1]+1]>M and u[L[0]][L[1]+1]==F:M,P=s[L[0]][L[1]+1],[L[0],L[1]+1]
if M<1: break
u[P[0]][P[1]]=T
p*=s[P[0]][P[1]]
l+=[P]
else:A.append([p,l])
A.sort()
u=[[F for i in r(W)] for j in r(H)]
for d in reversed(A):
L=d[1]
for g in L:
if u[g[0]][g[1]]: break
else:
a+=[L]
for g in L: u[g[0]][g[1]]=True
print(len(a))
for i in a:
for j in r(K):print(str(i[j][0]+1)+" "+str(i[j][1]+1))